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Han P, Mao X, Jin Y, Sarina S, Jia J, Waclawik ER, Du A, Bottle SE, Zhao JC, Zhu HY. Plasmonic Silver-Nanoparticle-Catalysed Hydrogen Abstraction from the C(sp 3 )-H Bond of the Benzylic C α atom for Cleavage of Alkyl Aryl Ether Bonds. Angew Chem Int Ed Engl 2023; 62:e202215201. [PMID: 36450692 PMCID: PMC10108273 DOI: 10.1002/anie.202215201] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/27/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
Selective activation of the C(sp3 )-H bond is an important process in organic synthesis, where efficiently activating a specific C(sp3 )-H bond without causing side reactions remains one of chemistry's great challenges. Here we report that illuminated plasmonic silver metal nanoparticles (NPs) can abstract hydrogen from the C(sp3 )-H bond of the Cα atom of an alkyl aryl ether β-O-4 linkage. The intense electromagnetic near-field generated at the illuminated plasmonic NPs promotes chemisorption of the β-O-4 compound and the transfer of photo-generated hot electrons from the NPs to the adsorbed molecules leads to hydrogen abstraction and direct cleavage of the unreactive ether Cβ -O bond under moderate reaction conditions (≈90 °C). The plasmon-driven process has certain exceptional features: enabling hydrogen abstraction from a specific C(sp3 )-H bond, along with precise scission of the targeted C-O bond to form aromatic compounds containing unsaturated, substituted groups in excellent yields.
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Affiliation(s)
- Pengfei Han
- College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.,School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Xin Mao
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Yichao Jin
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Sarina Sarina
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Jianfeng Jia
- School of Chemical and Material Science, Shanxi Normal University, Linfen, 041000, P. R. China
| | - Eric R Waclawik
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Aijun Du
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Steven E Bottle
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Jin-Cai Zhao
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China
| | - Huai-Yong Zhu
- School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD 4001, Australia
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Dong J, Li R, Sun F, Jiang Y, Wu H. Structures, fluorescence, and superoxide radical scavenging activities of two cd–Ln (Ln = Gd, Er) coordination polymers with an open-chain ether Schiff base and isonicotinate. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2036980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Jianping Dong
- School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, PR China
| | - Ruixue Li
- School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, PR China
| | - Fugang Sun
- School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, PR China
| | - Yuxuan Jiang
- School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, PR China
| | - Huilu Wu
- School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou, PR China
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Addition of Popular Exogenous Antioxidant Agent, PBN, to Culture Media May Be an Important Step to Optimization of Myogenic Stem/Progenitor Cell Preparation Protocol. Antioxidants (Basel) 2021; 10:antiox10060959. [PMID: 34203726 PMCID: PMC8232265 DOI: 10.3390/antiox10060959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 11/17/2022] Open
Abstract
The aim of the study was to modify human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) and demonstrate the optimal cell preparation protocol for application in post-infarction hearts. We used conditioned SkMDS/PC culture medium with α-phenyl-N-tert-butyl nitrone (PBN). SkMDS/PCs were cultured under hypoxic conditions and the results were compared to the standard ones. We observed a significant increase of CD-56 positive phenotypic marker the ability to form functional myotubes, increase in the proportion of young cells in cell primary suspensions, and a decrease in the percentage of apoptotic cells among PBN-conditioned cells in normoxia an hypoxia. We also observed significantly higher levels of SOD3 expression; maintained expression of SOD1, SOD2, and CAT; a higher level of BCL2 gene expression; and a rather significant decrease in Hsp70 gene expression in PBN-conditioned SkMDS/PCs compared to the WT population under hypoxic conditions. In addition, significant increase of myogenic genes expression was observed after PBN addition to culture medium, compared to WT population under hypoxia. Interestingly, PBN addition significantly increased the lengths of telomeres under hypoxia. Based on the data obtained, we can postulate that PBN conditioning of human SkMDS/PCs could be a promising step in improving myogenic cell preparation protocol for pro-regenerative treatment of post-infarction hearts.
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Deletraz A, Zéamari K, Hua K, Combes M, Villamena FA, Tuccio B, Callizot N, Durand G. Substituted α-Phenyl and α-Naphthlyl- N- tert-butyl Nitrones: Synthesis, Spin-Trapping, and Neuroprotection Evaluation. J Org Chem 2020; 85:6073-6085. [PMID: 32267700 DOI: 10.1021/acs.joc.0c00563] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
New derivatives of α-phenyl-N-tert-butyl nitrone (PBN) bearing a hydroxyl, an acetate, or an acetamide substituent on the N-tert-butyl moiety and para-substituted phenyl or naphthlyl moieties were synthesized. Their ability to trap hydroxymethyl radical was evaluated by electron paramagnetic resonance spectroscopy. The presence of two electron-withdrawing substituents on both sides of the nitronyl function improves the spin-trapping properties, with 4-HOOC-PBN-CH2OAc and 4-HOOC-PBN-CH2NHAc being ∼4× more reactive than PBN. The electrochemical properties of the derivatives were further investigated by cyclic voltammetry and showed that the redox potentials of the nitrones are largely influenced by the nature of the substituents both on the aromatic ring and on the N-tert-butyl function. The acetamide derivatives PBN-CH2NHAc, 4-AcNHCH2-PBN-CH2NHAc, and 4-MeO-PBN-CH2NHAc were the easiest to oxidize. A computational approach was used to rationalize the effect of functionalization on the free energies of nitrone reactivity with hydroxymethyl radical as well as on the electron affinity and ionization potential. Finally, the neuroprotection of the derivatives was evaluated in an in vitro model of cellular injury on cortical neurons. Five derivatives showed good protection at very low concentrations (0.1-10 μM), with PBN-CH2NHAc and 4-HOOC-PBN being the two most promising agents.
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Affiliation(s)
- Anaïs Deletraz
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université, Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza, BP 21239, Avignon 84916 Cedex 9, France
| | - Kamal Zéamari
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université, Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza, BP 21239, Avignon 84916 Cedex 9, France
| | - Kangyu Hua
- The Ohio State University, Department of Biological Chemistry and Pharmacology, 473 West 12th Avenue, Columbus, Ohio 43210, United States
| | - Maud Combes
- Neuro-Sys, 410 Chemin Départemental 60, 13120 Gardanne, France
| | - Frederick A Villamena
- The Ohio State University, Department of Biological Chemistry and Pharmacology, 473 West 12th Avenue, Columbus, Ohio 43210, United States
| | - Béatrice Tuccio
- Aix-Marseille Université, CNRS, ICR UMR 7273, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20, France
| | - Noelle Callizot
- Neuro-Sys, 410 Chemin Départemental 60, 13120 Gardanne, France
| | - Grégory Durand
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM & Avignon Université, Equipe Chimie Bioorganique et Systèmes Amphiphiles, 301 rue Baruch de Spinoza, BP 21239, Avignon 84916 Cedex 9, France
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Gromov OI, Kuzin SV, Golubeva EN. Performance of DFT methods in the calculation of isotropic and dipolar contributions to 14N hyperfine coupling constants of nitroxide radicals. J Mol Model 2019; 25:93. [PMID: 30859325 DOI: 10.1007/s00894-019-3966-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/07/2019] [Indexed: 10/27/2022]
Abstract
In the present study, we tested the widely used density functionals BP86, PBE, OLYP, TPSS, M06-L, B3LYP, PBE0, mPW1PW, B97, BHandHLYP, TPSS0, M06, M06-2X, CAM-B3LYP, ωB97x, and B2PLYP with the cc-pCVQZ basis set in calculations on a set of 23 nitroxide radicals with well-resolved 14N anisotropic hyperfine coupling (HFC) constants. The results were compared with those obtained using the B3LYP/N07D and PBE/N07D methods. The convergence of the HFC values to the complete basis set limit is briefly discussed. The best results were obtained using the M06/COSMO method, with a mean absolute deviation (MAD) of 0.4 G for the dipole-dipole contribution and MAD = 0.6 G for the contact coupling contribution (as compared to 1.1 G and 1.0 G, respectively, for the B3LYP/N07D/COSMO method and 1.7 G and 0.5 G, respectively, for the B3LYP/N07D method). The majority of the functionals yielded satisfactory results for the dipole-dipole contribution, but only the M06 functional yielded similar errors for both the dipole-dipole and isotropic contributions. The RIJCOSX and RI approximations introduced errors equal to or smaller than 0.01 G.
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Affiliation(s)
- Oleg I Gromov
- Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991.
| | - Sergei V Kuzin
- Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991
| | - Elena N Golubeva
- Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russia, 119991
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6
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Lescic S, Karoui H, Hardy M, Charles L, Tordo P, Ouari O, Gaudel-Siri A, Siri D. Alkylperoxyl spin adducts of pyrroline-N-oxide spin traps: Experimental and theoretical CASSCF study of the unimolecular decomposition in organic solvent, potential applications in water. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sergiu Lescic
- Aix-Marseille University, CNRS, ICR; Marseille France
| | - Hakim Karoui
- Aix-Marseille University, CNRS, ICR; Marseille France
| | - Micaël Hardy
- Aix-Marseille University, CNRS, ICR; Marseille France
| | | | - Paul Tordo
- Aix-Marseille University, CNRS, ICR; Marseille France
| | - Olivier Ouari
- Aix-Marseille University, CNRS, ICR; Marseille France
| | | | - Didier Siri
- Aix-Marseille University, CNRS, ICR; Marseille France
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7
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Use of spin traps to detect superoxide production in living cells by electron paramagnetic resonance (EPR) spectroscopy. Methods 2016; 109:31-43. [DOI: 10.1016/j.ymeth.2016.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 01/23/2023] Open
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8
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Feng W, Ren C, Wang W, Guo C, Sun Q, Li P. An identification of the C–C bonding spin adduct in the spin trapping of N-methyl benzohydroxamic acid radical by 5,5-dimethyl-1-pyrroline N-oxide. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1944-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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On the vasoprotective mechanisms underlying novel β-phosphorylated nitrones: Focus on free radical characterization, scavenging and NO-donation in a biological model of oxidative stress. Eur J Med Chem 2016; 119:197-217. [PMID: 27162124 DOI: 10.1016/j.ejmech.2016.04.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 01/02/2023]
Abstract
A series of new hybrid 2-(diethoxyphosphoryl)-N-(benzylidene)propan-2-amine oxide derivatives with different aromatic substitution (PPNs) were synthesized. These molecules were evaluated for their EPR spin trapping potential on eleven different radicals and NO-donation properties in vitro, cytotoxicity and vasoprotective effect on precontracted rat aortic rings. A subfamily of the new PPNs featured an antioxidant moiety occurring in natural phenolic acids. From the experimental screening of these hydroxyphenyl- and methoxyphenyl-substituted PPNs, biocompatible nitrones 4d, and 4g-4i deriving from caffeic, gallic, ferulic and sinapic acids, which combined improved EPR probing of ROS formation, vasorelaxant action and antioxidant potency, might be potential drug candidate alternatives to PBN and its analogues.
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Rosselin M, Tuccio B, Pério P, Villamena FA, Fabre PL, Durand G. Electrochemical and Spin-Trapping Properties of para-substituted α-Phenyl-N-tert-butyl Nitrones. Electrochim Acta 2016. [DOI: 10.1016/j.electacta.2016.02.038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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Feng W, Ren C, Wang W, Guo C, Sun Q, Li P. Theoretical studies on the spin trapping of the 2-chloro-5-hydroxy-1,4-benzoquinone radical by 5,5-dimethyl-1-pyrroline N-oxide (DMPO): the identification of the C–O bonding spin adduct. RSC Adv 2016. [DOI: 10.1039/c6ra07696c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The C–O bonding spin adduct has been identified in the spin trapping of 2-chloro-5-hydroxy-1,4-benzoquinone radical by DMPO.
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Affiliation(s)
- Wenling Feng
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Cong Ren
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Weihua Wang
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Chao Guo
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
| | - Qiao Sun
- Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions
- School for Radiological and Interdisciplinary Sciences
- Soochow University
- Suzhou
- P. R. China
| | - Ping Li
- Key Laboratory of Life-Organic Analysis
- School of Chemistry and Chemical Engineering
- Qufu Normal University
- Qufu
- P. R. China
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Witwicki M. Theoretical Characterisation of Phosphinyl Radicals and Their Magnetic Properties: g Matrix. Chemphyschem 2015; 16:1912-25. [PMID: 25873130 DOI: 10.1002/cphc.201500121] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Indexed: 11/11/2022]
Abstract
The g matrices (g tensors) of various phosphinyl radicals (R2 P(.) ) were calculated using the DFT and multireference configuration interaction (MRCI) methods. The g matrices were distinctly dependent on the molecular structure of the radical. To thoroughly examine this dependence, the contributions from individual atoms and excited states were calculated. The former revealed the gain from the phosphorus atom to be preeminent unless PO or PS bonds are present in the radical molecule. The contributions owing to excited states arising from electronic transitions between doubly occupied molecular orbitals and the SOMO were clearly positive, as in the case of semiquinone and niroxide radicals. The transitions from the phosphorus lone pair were of paramount importance. Surprisingly, unlike for semiquinones and nitroxides, a significant negative contribution was observed from excitations from the SOMO to unoccupied molecular orbitals. For radicals with PO bonds, this contribution to the g2 component was dominant.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, 14 F. Joliot-Curie St., Wroclaw 50-283 (Poland).
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Bors I, Kaizer J, Speier G. Kinetics and mechanism of PPh3 oxygenation with 3O2 catalyzed by a 1,3,2-oxazaphosphole as flavin mimic. RSC Adv 2014. [DOI: 10.1039/c4ra01320d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
1,3,2-Oxazaphosphole catalyse the oxygenation of triphenylphosphine to its oxide by molecular oxygen.
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Affiliation(s)
- I. Bors
- Department of Chemistry
- University of Pannonia
- , Hungary
| | - J. Kaizer
- Department of Chemistry
- University of Pannonia
- , Hungary
| | - G. Speier
- Department of Chemistry
- University of Pannonia
- , Hungary
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14
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Indo HP, Nakanishi I, Ohkubo K, Yen HC, Nyui M, Manda S, Matsumoto KI, Fukuhara K, Anzai K, Ikota N, Matsui H, Minamiyama Y, Nakajima A, Ichikawa H, Fukuzumi S, Ozawa T, Mukai C, Majima HJ. Comparison of in vivo and in vitro antioxidative parameters for eleven food factors. RSC Adv 2013. [DOI: 10.1039/c3ra22686g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Diesterified nitrone rescues nitroso-redox levels and increases myocyte contraction via increased SR Ca(2+) handling. PLoS One 2012; 7:e52005. [PMID: 23300588 PMCID: PMC3531448 DOI: 10.1371/journal.pone.0052005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 11/07/2012] [Indexed: 01/06/2023] Open
Abstract
Nitric oxide (NO) and superoxide (O2−) are important cardiac signaling molecules that regulate myocyte contraction. For appropriate regulation, NO and O2.− must exist at defined levels. Unfortunately, the NO and O2.− levels are altered in many cardiomyopathies (heart failure, ischemia, hypertrophy, etc.) leading to contractile dysfunction and adverse remodeling. Hence, rescuing the nitroso-redox levels is a potential therapeutic strategy. Nitrone spin traps have been shown to scavenge O2.− while releasing NO as a reaction byproduct; and we synthesized a novel, cell permeable nitrone, 2–2–3,4-dihydro-2H-pyrrole 1-oxide (EMEPO). We hypothesized that EMEPO would improve contractile function in myocytes with altered nitroso-redox levels. Ventricular myocytes were isolated from wildtype (C57Bl/6) and NOS1 knockout (NOS1−/−) mice, a known model of NO/O2.− imbalance, and incubated with EMEPO. EMEPO significantly reduced O2.− (lucigenin-enhanced chemiluminescence) and elevated NO (DAF-FM diacetate) levels in NOS1−/− myocytes. Furthermore, EMEPO increased NOS1−/− myocyte basal contraction (Ca2+ transients, Fluo-4AM; shortening, video-edge detection), the force-frequency response and the contractile response to β-adrenergic stimulation. EMEPO had no effect in wildtype myocytes. EMEPO also increased ryanodine receptor activity (sarcoplasmic reticulum Ca2+ leak/load relationship) and phospholamban Serine16 phosphorylation (Western blot). We also repeated our functional experiments in a canine post-myocardial infarction model and observed similar results to those seen in NOS1−/− myocytes. In conclusion, EMEPO improved contractile function in myocytes experiencing an imbalance of their nitroso-redox levels. The concurrent restoration of NO and O2.− levels may have therapeutic potential in the treatment of various cardiomyopathies.
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Potential implication of the chemical properties and bioactivity of nitrone spin traps for therapeutics. Future Med Chem 2012; 4:1171-207. [PMID: 22709256 DOI: 10.4155/fmc.12.74] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nitrone therapeutics has been employed in the treatment of oxidative stress-related diseases such as neurodegeneration, cardiovascular disease and cancer. The nitrone-based compound NXY-059, which is the first drug to reach clinical trials for the treatment of acute ischemic stroke, has provided promise for the development of more robust pharmacological agents. However, the specific mechanism of nitrone bioactivity remains unclear. In this review, we present a variety of nitrone chemistry and biological activity that could be implicated for the nitrone's pharmacological activity. The chemistries of spin trapping and spin adduct reveal insights on the possible roles of nitrones for altering cellular redox status through radical scavenging or nitric oxide donation, and their biological effects are presented. An interdisciplinary approach towards the development of novel synthetic antioxidants with improved pharmacological properties encompassing theoretical, synthetic, biochemical and in vitro/in vivo studies is covered.
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Nash KM, Rockenbauer A, Villamena FA. Reactive nitrogen species reactivities with nitrones: theoretical and experimental studies. Chem Res Toxicol 2012; 25:1581-97. [PMID: 22775566 DOI: 10.1021/tx200526y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Reactive nitrogen species (RNS) such as nitrogen dioxide ((•)NO(2)), peroxynitrite (ONOO(-)), and nitrosoperoxycarbonate (ONOOCO(2)(-)) are among the most damaging species present in biological systems due to their ability to cause modification of key biomolecular systems through oxidation, nitrosylation, and nitration. Nitrone spin traps are known to react with free radicals and nonradicals via electrophilic and nucleophilic addition reactions and have been employed as reagents to detect radicals using electron paramagnetic resonance (EPR) spectroscopy and as pharmacological agents against oxidative stress-mediated injury. This study examines the reactivity of cyclic nitrones such as 5,5-dimethylpyrroline N-oxide (DMPO) with (•)NO(2), ONOO(-), ONOOCO(2)(-), SNAP, and SIN-1 using EPR. The thermochemistries of nitrone reactivity with RNS and isotropic hfsc's of the addition products were also calculated at the PCM(water)/B3LYP/6-31+G**//B3LYP/6-31G* level of theory with and without explicit water molecules to rationalize the nature of the observed EPR spectra. Spin trapping of other RNS such as azide ((•)N(3)), nitrogen trioxide ((•)NO(3)), amino ((•)NH(2)) radicals and nitroxyl (HNO) were also theoretically and experimentally investigated by EPR spin trapping and mass spectrometry. This study also shows that other spin traps such as 5-carbamoyl-5-methyl-pyrroline N-oxide, 5-ethoxycarbonyl-5-methyl-pyrroline N-oxide, and 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline N-oxide can react with radical and nonradical RNS, thus making spin traps suitable probes as well as antioxidants against RNS-mediated oxidative damage.
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Affiliation(s)
- Kevin M Nash
- Department of Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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18
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Zamora PL, Villamena FA. Theoretical and experimental studies of the spin trapping of inorganic radicals by 5,5-dimethyl-1-pyrroline N-oxide (DMPO). 3. Sulfur dioxide, sulfite, and sulfate radical anions. J Phys Chem A 2012; 116:7210-8. [PMID: 22668066 PMCID: PMC3428032 DOI: 10.1021/jp3039169] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Radical forms of sulfur dioxide (SO(2)), sulfite (SO(3)(2-)), sulfate (SO(4)(2-)), and their conjugate acids are known to be generated in vivo through various chemical and biochemical pathways. Oxides of sulfur are environmentally pervasive compounds and are associated with a number of health problems. There is growing evidence that their toxicity may be mediated by their radical forms. Electron paramagnetic resonance (EPR) spin trapping using the commonly used spin trap, 5,5-dimethyl-1-pyrroline N-oxide (DMPO), has been employed in the detection of SO(3)(•-) and SO(4)(•-). The thermochemistries of SO(2)(•-), SO(3)(•-), SO(4)(•-), and their respective conjugate acids addition to DMPO were predicted using density functional theory (DFT) at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level. No spin adduct was observed for SO(2)(•-) by EPR, but an S-centered adduct was observed for SO(3)(•-)and an O-centered adduct for SO(4)(•-). Determination of adducts as S- or O-centered was made via comparison based on qualitative trends of experimental hfcc's with theoretical values. The thermodynamics of the nonradical addition of SO(3)(2-) and HSO(3)(-) to DMPO followed by conversion to the corresponding radical adduct via the Forrester-Hepburn mechanism was also calculated. Adduct acidities and decomposition pathways were investigated as well, including an EPR experiment using H(2)(17)O to determine the site of hydrolysis of O-centered adducts. The mode of radical addition to DMPO is predicted to be governed by several factors, including spin population density, and geometries stabilized by hydrogen bonds. The thermodynamic data supports evidence for the radical addition pathway over the nucleophilic addition mechanism.
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Affiliation(s)
- Pedro L. Zamora
- Department of Pharmacology, The Davis Heart and Lung Research Institute and Center for Biomedical EPR Spectroscopy and Imaging, College of Medicine, The Ohio State University, Columbus, Ohio, USA 43210
| | - Frederick A. Villamena
- Department of Pharmacology, The Davis Heart and Lung Research Institute and Center for Biomedical EPR Spectroscopy and Imaging, College of Medicine, The Ohio State University, Columbus, Ohio, USA 43210
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Das A, Gopalakrishnan B, Voss OH, Doseff AI, Villamena FA. Inhibition of ROS-induced apoptosis in endothelial cells by nitrone spin traps via induction of phase II enzymes and suppression of mitochondria-dependent pro-apoptotic signaling. Biochem Pharmacol 2012; 84:486-97. [PMID: 22580046 DOI: 10.1016/j.bcp.2012.04.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Revised: 04/27/2012] [Accepted: 04/30/2012] [Indexed: 12/30/2022]
Abstract
Oxidative stress is the main etiological factor behind the pathogenesis of various diseases including inflammation, cancer, cardiovascular and neurodegenerative disorders. Due to the spin trapping abilities and various pharmacological properties of nitrones, their application as therapeutic agent has been gaining attention. Though the antioxidant properties of the nitrones are well known, the mechanism by which they modulate the cellular defense machinery against oxidative stress is not well investigated and requires further elucidation. Here, we have investigated the mechanisms of cytoprotection of the nitrone spin traps against oxidative stress in bovine aortic endothelial cells (BAEC). Cytoprotective properties of both the cyclic nitrone 5,5-dimethyl-pyrroline N-oxide (DMPO) and linear nitrone α-phenyl N-tert-butyl nitrone (PBN) against H₂O₂-induced cytotoxicity were investigated. Preincubation of BAEC with PBN or DMPO resulted in the inhibition of H₂O₂-mediated cytotoxicity and apoptosis. Nitrone-treatment resulted in the induction and restoration of phase II antioxidant enzymes via nuclear translocation of NF-E2-related factor 2 (Nrf-2) in oxidatively-challenged cells. Furthermore, the nitrones were found to inhibit the mitochondrial depolarization and subsequent activation of caspase-3 induced by H₂O₂. Significant down-regulation of the pro-apoptotic proteins p53 and Bax, and up-regulation of the anti-apoptotic proteins Bcl-2 and p-Bad were observed when the cells were preincubated with the nitrones prior to H₂O₂-treatment. It was also observed that Nrf-2 silencing completely abolished the protective effects of nitrones. Hence, these findings suggest that nitrones confer protection to the endothelial cells against oxidative stress by modulating phase II antioxidant enzymes and subsequently inhibiting mitochondria-dependent apoptotic cascade.
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Affiliation(s)
- Amlan Das
- Department of Pharmacology, and Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, USA
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Kim SU, Liu Y, Nash KM, Zweier JL, Rockenbauer A, Villamena FA. Fast reactivity of a cyclic nitrone-calix[4]pyrrole conjugate with superoxide radical anion: theoretical and experimental studies. J Am Chem Soc 2010; 132:17157-73. [PMID: 21070040 PMCID: PMC3121924 DOI: 10.1021/ja105198c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitrone spin traps have been employed as probes for the identification of transient radical species in chemical and biological systems using electron paramagnetic resonance (EPR) spectroscopy and have exhibited pharmacological activity against oxidative-stress-mediated diseases. Since superoxide radical anion (O2(•-)) is a major precursor to most reactive oxygen species and calix[4]pyrroles have been shown to exhibit high affinity to anions, a cyclic nitrone conjugate of calix[4]pyrrole (CalixMPO) was designed, synthesized, and characterized. Computational studies at the PCM/B3LYP/6-31+G(d,p)//B3LYP/6-31G(d) level suggest a pendant-type linkage between the calix[4]pyrrole and the nitrone to be the most efficient design for spin trapping of O2(•-), giving exoergic reaction enthalpies (ΔH(298K,aq)) and free energies (ΔG(298K,aq)) of -16.9 and -2.1 kcal/mol, respectively. (1)H NMR study revealed solvent-dependent conformational changes in CalixMPO leading to changes in the electronic properties of the nitronyl group upon H-bonding with the pyrrole groups as also confirmed by calculations. CalixMPO spin trapping of O2(•-) exhibited robust EPR spectra. Kinetic analysis of O2(•-) adduct formation and decay in polar aprotic solvents using UV-vis stopped-flow and EPR methods gave a larger trapping rate constant for CalixMPO and a longer half-life for its O2(•-) adduct compared to the commonly used nitrones. The unusually high reactivity of CalixMPO with O2(•-) was rationalized to be due to the synergy between the α-effect and electrostatic effect by the calix[4]pyrrole moiety on O2(•-) and the nitrone, respectively. This work demonstrates for the first time the application of an anion receptor for the detection of one of the most important radical intermediates in biological and chemical systems (i.e., O2(•-)).
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Affiliation(s)
- Shang-U Kim
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Yangping Liu
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Kevin M. Nash
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Jay L. Zweier
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Antal Rockenbauer
- Chemical Research Center, Institute of Structural Chemistry, H-1025 Budapest, Pusztaszeri 59, Hungary
| | - Frederick A. Villamena
- Department of Pharmacology, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
- Center for Biomedical EPR Spectroscopy and Imaging, Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, OH, 43210, USA
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Szterk A, Stefaniuk I, Waszkiewicz-Robak B, Roszko M. Oxidative Stability of Lipids by Means of EPR Spectroscopy and Chemiluminescence. J AM OIL CHEM SOC 2010. [DOI: 10.1007/s11746-010-1715-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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